European Bilateral Pediatric Cochlear Implant Forum Consensus Statement

International Consensus Statements on Intraoperative Testing for Cochlear Implantation Surgery

OBJECTIVES

A wide variety of intraoperative tests are available in cochlear implantation. However, no consensus exists on which tests constitute the minimum necessary battery. We assembled an international panel of clinical experts to develop, refine, and vote upon a set of core consensus statements.

DESIGN

A literature review was used to identify intraoperative tests currently used in the field and draft a set of provisional statements. For statement evaluation and refinement, we used a modified Delphi consensus panel structure. Multiple interactive rounds of voting, evaluation, and feedback were conducted to achieve convergence.

RESULTS

Twenty-nine provisional statements were included in the original draft. In the first voting round, consensus was reached on 15 statements. Of the 14 statements that did not reach consensus, 12 were revised based on feedback provided by the expert practitioners, and 2 were eliminated. In the second voting round, 10 of the 12 revised statements reached a consensus. The two statements which did not achieve consensus were further revised and subjected to a third voting round. However, both statements failed to achieve consensus in the third round. In addition, during the final revision, one more statement was decided to be deleted due to overlap with another modified statement.

CONCLUSIONS

A final core set of 24 consensus statements was generated, covering wide areas of intraoperative testing during CI surgery. These statements may provide utility as evidence-based guidelines to improve quality and achieve uniformity of surgical practice.

Simultaneous versus Sequential Cochlear Implantation in Adults: Quantitative and Qualitative Outcomes

OBJECTIVE

To compare speech recognition and quality of life outcomes between bilateral sequentially and simultaneously implanted adult cochlear implant (CI) recipients who initially qualify for a CI in both ears.

STUDY DESIGN

Retrospective chart review.

SETTING

Tertiary referral center.

METHODS

Retrospective chart review identified adults who underwent bilateral CI, either simultaneously or sequentially, at a high-volume center between 2012 and 2022. Sequentially implanted patients were only included if the second ear qualified for CI in quiet (defined as best-aided AzBio quiet testing <60%), at time of initial CI evaluation.

RESULTS

Of 112 bilateral CI patients who qualified in both ears at initial evaluation, 95 underwent sequential implantation and 17 simultaneous. Age, duration, and etiology of hearing loss, and CI usage were similar between groups. Preoperatively, the sequential group had lower pure-tone average (PTA) in the 1st ear than the simultaneously implanted group (P = <.001) but, no difference in 2nd ear PTA (P = .657). Preoperative speech recognition scores were significantly higher for the sequential group; however, this was not true for postoperative scores. There was no difference in the proportion of patients showing significant CI-only or bilateral performance improvement between the groups. Both groups demonstrated similar benefit in quality of life measures.

CONCLUSION

Our findings indicate both simultaneous and sequential cochlear implantation are effective in improving hearing performance and quality of life. Thus, bilateral versus simultaneous implantation should be discussed and tailored for each individual patient.

Minimum intraoperative testing battery for cochlear implantation: the international practice trend

PURPOSE

In cochlear implantation (CI) surgery, there are a wide variety of intraoperative tests available. However, no clear guide exists on which tests must be performed as the minimum intraoperative testing battery. Toward this end, we studied the usage patterns, recommendations, and attitudes of practitioners toward intraoperative testing.

METHODS

This study is a multicentric international survey of tertiary referral CI centers. A survey was developed and administered to a group of CI practitioners (n = 34) including otologists, audiologists and biomedical engineers. Thirty six participants were invited to participate in this study based on a their scientific outputs to the literature on the intraoperative testing in CI field and based on their high load of CI surgeries. Thirty four, from 15 countries have accepted the invitation to participate. The participants were asked to indicate the usage trends, perceived value, influence on decision making and duration of each intraoperative test. They were also asked to indicate which tests they believe should be included in a minimum test battery for routine cases.

RESULTS

Thirty-two (94%) experts provided responses. The most frequently recommended tests for a minimum battery were facial nerve monitoring, electrode impedance measurements, and measurements of electrically evoked compound action potentials (ECAPs). The perceived value and influence on surgical decision-making also varied, with high-resolution CT being rated the highest on both measures.

CONCLUSION

Facial nerve monitoring, electrode impedance measurements, and ECAP measurements are currently the core tests of the intraoperative test battery for CI surgery.

Costs analysis of cochlear implantation in children

OBJECTIVES

The study assessed the direct medical costs of the cochlear implantation pathway from the healthcare payer's perspective, in children with bilateral severe to profound hearing loss, from diagnosis to 3 years' follow-up after first implantation. We also compared costs between two populations: congenital and progressive deafness.

MATERIAL AND METHODS

A retrospective costs analysis was performed for 56 children who received a cochlear implant in one French pediatric ENT center. The children had severe to profound hearing loss, and were implanted before the age of 10 years. We calculated direct medical costs in 3 phases: diagnosis to pre-implantation assessment, surgical and hospital management of implantation, and 3 years' follow-up.

RESULTS

Mean costs were €64,675 (range, €38,709-113,954) per child from diagnosis to 3 years after first implantation. Mean costs in congenital deafness detected on neonatal screening and on progressive deafness were respectively €65,420 and €63,930 (P=0.7).

CONCLUSION

The global cost was €64,675 per child from diagnosis to 3 years after first implantation. There was no difference in cost according to congenital versus progressive hearing loss.

Similar performance in sound localisation with unsynchronised and synchronised automatic gain controls in bilateral cochlear implant recipients

OBJECTIVE

One proposed method to improve sound localisation for bilateral cochlear implant (BiCI) users is to synchronise the automatic gain control (AGC) of both audio processors. In this study we tested whether AGC synchronisation in a dual-loop front-end processing scheme with a 3:1 compression ratio improves sound localisation acuity.

DESIGN

Source identification in the frontal hemifield was tested in in an anechoic chamber as a function of (roving) presentation level. Three different methods of AGC synchronisation were compared to the standard unsynchronised approach. Both root mean square error (RMSE) and signed bias were calculated to evaluate sound localisation in the horizontal plane.

STUDY SAMPLE

Six BiCI users.

RESULTS

None of the three AGC synchronisation methods yielded significant improvements in either localisation error or bias, neither across presentation levels nor for individual presentation levels. For synchronised AGC, the pooled mean (standard deviation) localisation error of the three synchronisation methods was 24.7 (5.8) degrees RMSE, for unsynchronised AGC it was 27.4 (7.5) degrees. The localisation bias was 5.1 (5.5) degrees for synchronised AGC and 5.0 (3.8) for unsynchronised.

CONCLUSIONS

These findings do not support the hypothesis that the tested AGC synchronisation configurations improves localisation acuity in bilateral users of MED-EL cochlear implants.

Cost-Utility Analysis of Bilateral Cochlear Implants for Children With Severe-to-Profound Sensorineural Hearing Loss in Taiwan

OBJECTIVES

Cochlear implants are an option for children with sensorineural hearing loss who do not benefit from hearing aids. Although bilateral cochlear implantation (CI) has been shown to enhance hearing performance and quality of life, its cost-effectiveness remains unclear. This study aimed to evaluate the cost-effectiveness of bilateral CI compared with bimodal hearing for children with sensorineural hearing loss in Taiwan from both the perspectives of patients and Taiwan's National Health Insurance Administration (TNHIA).

DESIGN

A four-state Markov model was utilized in the study, including "use the first internal device," "use the second internal device," "use the third internal device," and "death." Health utility values were obtained from a local survey of health professionals and then adjusted by a scale to reflect both the negative impact of aging on hearing and the time needed to develop the full benefit of treatment in the earliest years of life. The cost data were derived from a caregiver survey, hospital databases, clinical experts, and the TNHIA. The incremental cost-effectiveness ratio (ICER) was calculated over the lifetime horizon and presented as cost per quality-adjusted life year (QALY) to evaluate the cost-effectiveness of simultaneous bilateral CI, sequential bilateral CI, and bimodal hearing. In addition, one-way sensitivity analyses and probabilistic sensitivity analyses were conducted to investigate the impact of uncertainty and the robustness of the model.

RESULTS

The base-case analysis showed that children with bilateral CI gained more QALYs while incurring more costs when compared with those with bimodal hearing. From the TNHIA perspective, compared with bimodal hearing, the ICER of simultaneous bilateral CI was New Taiwan Dollars 232,662 per QALY whereas from the patient perspective, the ICER was New Taiwan Dollars 1,006,965 per QALY. Moreover, simultaneous bilateral CI dominated sequential bilateral CI from both perspectives. Compared with bimodal hearing, the ICER of sequential bilateral CI did not exceed twice the gross domestic product per capita in Taiwan from either perspective. One-way sensitivity analysis demonstrated that the utility gain of bilateral CI compared with bimodal hearing was the most impactful parameter from both perspectives. Probabilistic sensitivity analysis confirmed the robustness of the base-case analysis results.

CONCLUSIONS

Our findings reveal that bilateral CI was cost-effective when using the threshold of one to three times the 2022 gross domestic product per capita in Taiwan from both the TNHIA and patient perspectives. Future research incorporating cost and effectiveness data from other dimensions is needed to help decision-makers assess the cost-effectiveness of bilateral CI more comprehensively.

Selection of the optimal first ear for sequential bilateral cochlear implantation in children

OBJECTIVES

When there is a difference in hearing on both ears, where to perform the first cochlear implantation (CI) becomes an important issue. The purpose of the study was to evaluate which ear should be chosen for the first implantation in sequential bilateral CI with a long inter-implant period.

METHODS

The study population consisted of 34 severe-to-profound sensorineural hearing loss pediatrics with the inter-implant period of ≥3 years between the first CI (CI-1) and the second CI (CI-2) before the age of 19 (mean of inter-implant period: 7.1-year). The patients were classified into Group A (CI-1 was performed on the ear with better hearing), Group B (CI-1 on the ear with worse hearing), or Group C (symmetrical hearing in both ears). Speech intelligibility test results were compared between the groups.

RESULTS

The monosyllabic word scores of CI-1 were excellent in Groups A (91.7±7.9%) and B (92.5±3.6%) but slightly lower in Group C (85.7±14.9%) before the second implantation (P = .487). At 3 years after the second implantation, all groups demonstrated excellent scores in the bilateral CI condition (95.9±3.0% in Group A; 99.1±.8% in Group B; 97.5±2.9% in Group C, P = .600). However, when the patients were tested in using CI-2 only in Groups A and B after using bilateral CI for 3 years, the scores were inconsistent in Group A (79.6±23.9%; range: 22.2-94.4%), while those were higher and more constant in Group B (92.9±4.8%; 86.8-100.0%).

CONCLUSIONS

The first CI is strongly recommended to perform on a worse hearing ear if they had different hearing levels between ears. Even with the first CI on a worse hearing ear, its performance never deteriorates. In addition, if they receive the second CI several years later, it will be likely that the second one functions better.

Importance of age at 2nd implantation and interimplant interval to the outcome of bilateral prelingually deafened pediatric cochlear implantation

BACKGROUND

In Taiwan, the number of cases of sequential bilateral pediatric cochlear implantation (CI) is increasing but data regarding its effectiveness and impact of the reimbursement policy are lacking. We examined the speech perception and quality of life (QOL) of bilateral prelingually deaf children who underwent sequential CI, considering the effects of age at the time of second implantation and interimplant interval.

METHODS

We enrolled 124 Mandarin-speaking participants who underwent initial cochlear implant (CI1) in 2001-2019 and a second CI (CI2) in 2015-2020. Patients were followed up for ≥2 years and were categorized into groups based on age at the time of CI2 implantation (<3.5, 3.6-7, 7.1-10, 10.1-13, and 13.1-18 years) and interimplant interval (0.5-3, 3.1-5, 5.1-7, 7.1-10, and >10 years). We evaluated speech perception, device usage rates, and QOL using subjective questionnaires (Speech, Spatial, and Qualities of Hearing and Comprehension Cochlear Implant Questionnaire).

RESULTS

Speech perception scores of CI2 were negatively correlated with ages at the time of CI1 and CI2 implantation and interimplant interval. Older age and a longer interimplant interval were associated with higher nonuse rates for CI2 and worse auditory performance and QOL. Among individuals aged >13 years with interimplant intervals >10 years, up to 44% did not use their second ear. Patients aged 7.1 to 10 years had better speech perception and higher questionnaire scores than those aged 10.1 to 13 and 13.1 to 18 years. Furthermore, patients aged 10.1 to 13 years had a lower rate of continuous CI2 usage compared to those aged 7.1 to 10 years.

CONCLUSION

Timely implantation of CI2 is essential to achieve optimal outcomes, particularly among sequentially implanted patients with long-term deafness in the second ear and no improvement with hearing aids following CI1 implantation. For CI2 implantation, an upper limit of age of 10 years and interimplant interval of 7 years are essential to prevent suboptimal outcomes. These data can provide useful information to implant recipients, their families, and medical and audiological professionals, enabling a comprehensive understanding of the benefits and potential impacts of the timing of CI2 implantation.

Hearing preservation in paediatric cochlear implantation with the Nucleus Slim Straight Electrode - our experience

OBJECTIVE

to evaluate the levels of successful hearing preservation and preservation of functional hearing following cochlear implantation (HPCI) in children using the Cochlear Nucleus® Slim Straight Electrode (SSE).

DESIGN

retrospective case note review of paediatric HPCI cases in our CI centre from 2013 to 2023. Inclusion criteria were attempted hearing preservation surgery, SSE used for implantation, pre-operative hearing thresholds ≤80dBHL at 250 Hz, CI before 18 years of age. Patients were excluded if no postoperative unaided PTA was obtained (poor attendance). Primairy outcome was hearing preservation using the HEARRING group formula; secondary outcome was residual functional hearing (≤80dBHL at 250 Hz/<90dB LFPTA).

STUDY SAMPLE

56 patients with 94 CI's were included for review.

RESULTS

Hearing preservation was achieved in 94.7% (89/94) of ears and complete preservation in 72% (68/94)). Average functional hearing was preserved in 89% using both criteria for preservation. Long-term follow up data was available for 36 ears (average 35.2 months), demonstrating 88.9% (32/36) complete preservation.

CONCLUSION

We have reliably achieved and maintained a high success rate of HPCI using the SSE in our paediatric population. The field of HPCI would benefit from unification of outcome reporting in order to optimise the evidence available to professionals, patients and their carers.

Recent advances in the application of MXenes for neural tissue engineering and regeneration

Transition metal carbides and nitrides (MXenes) are crystal nanomaterials with a number of surface functional groups such as fluorine, hydroxyl, and oxygen, which can be used as carriers for proteins and drugs. MXenes have excellent biocompatibility, electrical conductivity, surface hydrophilicity, mechanical properties and easy surface modification. However, at present, the stability of most MXenes needs to be improved, and more synthesis methods need to be explored. MXenes are good substrates for nerve cell regeneration and nerve reconstruction, which have broad application prospects in the repair of nervous system injury. Regarding the application of MXenes in neuroscience, mainly at the cellular level, the long-term in vivo biosafety and effects also need to be further explored. This review focuses on the progress of using MXenes in nerve regeneration over the last few years; discussing preparation of MXenes and their biocompatibility with different cells as well as the regulation by MXenes of nerve cell regeneration in two-dimensional and three-dimensional environments in vitro. MXenes have great potential in regulating the proliferation, differentiation, and maturation of nerve cells and in promoting regeneration and recovery after nerve injury. In addition, this review also presents the main challenges during optimization processes, such as the preparation of stable MXenes and long-term in vivo biosafety, and further discusses future directions in neural tissue engineering.

Emerging biotechnologies and biomedical engineering technologies for hearing reconstruction

Hearing impairment is a global health problem that affects social communications and the economy. The damage and loss of cochlear hair cells and spiral ganglion neurons (SGNs) as well as the degeneration of neurites of SGNs are the core causes of sensorineural hearing loss. Biotechnologies and biomedical engineering technologies provide new hope for the treatment of auditory diseases, which utilizes biological strategies or tissue engineering methods to achieve drug delivery and the regeneration of cells, tissues, and even organs. Here, the advancements in the applications of biotechnologies (including gene therapy and cochlear organoids) and biomedical engineering technologies (including drug delivery, electrode coating, electrical stimulation and bionic scaffolds) in the field of hearing reconstruction are presented. Moreover, we summarize the challenges and provide a perspective on this field.

Simultaneous Bilateral Cochlear Implantation in Adults

The objective of this study is to review our experience with simultaneous bilateral cochlear implantation (BiCI) in adults, and assess its feasibility. This could shorten the time required to regain binaural hearing, prevent social isolation, and potentially eliminate the need for hearing aids, as seen with sequential BiCI. A retrospective study was conducted involving adult patients who received simultaneous BiCI at our center between 2010 and 2023. The feasibility of simultaneous BiCI was assessed through postoperative clinical evaluations, outpatient visits, discharge status, and the acceptance of device fitting. Twenty-seven patients underwent simultaneous BiCIs. Their mean age was 37 years, comprising 59.3% males and 40.7% females. Out of the included patients, 51.9% had childhood-onset hearing loss, while 29.6% developed hearing loss later in life. Causes of hearing loss included meningitis 7.4%, trauma 11.1%, non-specific high-grade fever 11.1%, and Brucellosis infection 3.7%. Labyrinthine ossificans (LO) was present in 7.4%, and retrofenestral otospongiosis in 3.7%. The post-operative period and initial outpatient visit were uneventful for 88.8% and 81.5% of patients, respectively. Intraoperative complications were absent in 96.2% of cases. Simultaneous BiCI is feasible in adults without major intraoperative complications or troublesome recovery periods, offering potential benefits by reducing the number of surgeries and hospital admissions compared to the sequential method.

Simultaneous Bilateral Cochlear Implantation in Very Young Children Improves Adaptability and Social Skills: A Prospective Cohort Study

OBJECTIVES

To investigate the value of using the Gesell Development Diagnosis Scale (GDDS) to predict developmental outcomes in very young children who undergo simultaneous bilateral cochlear implantation.

DESIGN

In this prospective cohort study, a repeated-measures investigation was conducted in a tertiary referral hospital. A total of 62 children receiving simultaneous bilateral cochlear implantations were enrolled from April 2017 to August 2018. They were divided into 2 groups depending on the operative age: "Infants" group (6 to 12 months, N = 38) or "Children" group (12 to 36 months, N = 24). Data on the surgical outcomes, auditory development, speech production, and developmental indicators were collected until 2 years after the initial fitting. The primary outcome measure was the GDDS, a neuropsychological development examination. Secondary outcomes included the following: complication rate, aided pure-tone average, Infant-Toddler Meaningful Auditory Integration Scale, Categories of Auditory Performance-II, Meaningful Use of Speech Scale, Speech Intelligibility Rating, and the LittlEARS Auditory Questionnaire.

RESULTS

The mean ages at implantation in infants and children groups were 9.2 ± 1.17 and 16.6 ± 3.60 months, respectively. Significant differences were found in the social skills ( p = 0.001) and adaptability ( p = 0.031) domains of GDDS. The younger the age of bilateral cochlear implants surgery, the higher developmental quotient of language, social skills, and adaptability the child could achieve after 2 years. The complication rates in the infants and children groups were 0% versus 2.1% ( p = 0.57). There was no surgical complication in the infants group. In the children group, 1 case with enlarged vestibular aqueduct and Mondini malformation had a receiver-implant misplacement on the right side (2%, 1/48). In the two groups, auditory performance and speech production had improved similarly. In the infants group, social skills developmental quotient at baseline had a significant positive relationship with Meaningful Use of Speech Scale after 2 years.

CONCLUSIONS

Simultaneous bilateral cochlear implantation in younger children improves adaptability and social skills. GDDS is a sensitive tool of evaluating short-term effect of bilateral cochlear implants in neuropsychological development and constitutes a reliable predictor of speech production for the very younger pediatric cochlear implant users.

Health State Utility Values Associated with Cochlear Implants in Adults: A Systematic Review and Network Meta-Analysis

OBJECTIVES

The cost-effectiveness of bilateral cochlear implants in adults remains uncertain despite established clinical benefits. In cost-effectiveness studies, benefit is often measured by change in health state utility value (HSUV), a single number summary of health-related quality of life anchored at 0 (state of being dead) and 1 (perfect health). Small differences in bilateral cochlear implant HSUV change conclusions of published models, and invalid estimates can therefore mislead policy and funding decisions. As such, we aimed to review and synthesize published HSUV estimates associated with cochlear implants.

DESIGN

We included observational or experimental studies reporting HSUV for adult patients (age ≥18 years) with at least moderate-profound sensorineural hearing loss in both ears who received unilateral or bilateral cochlear implants. We searched MEDLINE, EMBASE, PsycINFO, and Cochrane Library databases up to May 1, 2021. Study and participant characteristics and HSUV outcomes were extracted. Narrative synthesis is reported for all studies. A Bayesian network meta-analysis was conducted to generate pooled estimates for the mean difference in HSUV for three comparisons: (1) unilateral cochlear implant versus preimplant, (2) bilateral cochlear implants versus preimplant, (3) bilateral versus unilateral cochlear implants. Our principal measure was pooled mean difference in HSUV.

RESULTS

Thirty-six studies reporting unique patient cohorts were identified. Health Utilities Index, 3 (HUI-3) was the most common HSUV elicitation method. HSUV from 19 preimplant mean estimates (1402 patients), 19 unilateral cochlear implant mean estimates (1701 patients), and 5 bilateral cochlear implants mean estimates (83 patients) were pooled to estimate mean differences in HUI-3 HSUV by network meta-analysis. Compared with preimplant, a unilateral cochlear implant was associated with a mean change in HSUV of +0.17 (95% credible interval [CrI] +0.12 to +0.23) and bilateral cochlear implants were associated with a mean change of +0.25 (95% CrI +0.12 to +0.37). No significant difference in HSUV was detected for bilateral compared with unilateral cochlear implants (+0.08 [95% CrI -0.06 to +0.21]). Overall study quality was moderate.

CONCLUSIONS

The findings of this review and network meta-analysis comprise the best-available resource for parameterization of cost-utility models of cochlear implantation in adults and highlight the need to critically evaluate the validity of available HSUV instruments for bilateral cochlear implant populations.Protocol registration: PROSPERO (CRD42018091838).

3D Ti3C2Tx MXene-Matrigel with Electroacoustic Stimulation to Promote the Growth of Spiral Ganglion Neurons

Cochlear implantation has become the most effective treatment method for patients with profound and total hearing loss. However, its therapeutic efficacy is dependent on the number and normal physiological function of cochlear implant-targeted spiral ganglion neurons (SGNs). Electrical stimulation can be used as an effective cue to regulate the morphology and function of excitatory cells. Therefore, it is important to develop an efficient cochlear implant electroacoustic stimulation (EAS) system to study the behavior of SGNs. In this work, we present an electrical stimulation system constructed by combining a cochlear implant and a conductive Ti₃C₂T_x MXene-matrigel hydrogel. SGNs were cultured in the Ti₃C₂T_x MXene-matrigel hydrogel and exposed to electrical stimulation transduced by the cochlear implant. It was demonstrated that low-frequency stimulation promoted the growth cone development and neurite outgrowth of SGNs as well as signal transmission between cells. This work may have potential value for the clinical application of the Ti₃C₂T_x MXene hydrogel to optimize the postoperative listening effect of cochlear implantation and benefit people with sensorineural hearing loss.

Benefit of sequential bilateral cochlear implantation in children between 5 to 18 years old: A prospective cohort study

Objective

To determine the benefit of sequential cochlear implantation after a long inter-implantation interval in children with bilateral deafness receiving their second implant between 5 and 18 years of age.

Study design

Prospective cohort-study.

Setting

Tertiary multicenter.

Patients

85 children with bilateral deafness and unilateral implantation receiving a contralateral cochlear implant at the age of 5 to 18 years.

Method

The primary outcomes were speech recognition in quiet and noise (CVC) scores. The secondary outcomes were language outcomes and subjective hearing abilities, all measured before and 12 months after sequential bilateral cochlear implantation. Medians of the paired data were compared using the Wilcoxon signed-rank test. Univariable linear regression analyses was used to analyze associations between variables and performance outcomes.

Results

A significant benefit was found for speech recognition in quiet (96% [89–98] vs 91% [85–96]; p < 0.01) and noise (65% [57–75] vs 54% [47–71]; p = 0.01) in the bilateral CI condition compared to unilateral (n = 75, excluded 10 non-users). No benefit was seen for language outcomes. The subjective sound quality score was statistically significant higher in bilateral compared to the unilateral CI condition. Pre-operative residual hearing level in the ear of the second implant, the inter-implant interval and age at time of second implantation was not significantly associated with performance scores.

Conclusion

After 12 months of use, sequential bilateral cochlear implantation showed improved speech perception in quiet and noise and improved subjective sound quality outcomes in children despite a great inter-implantation interval (median of 8 years [range 1–16 years]).

Cortical imbalance following delayed restoration of bilateral hearing in deaf adolescents

Unilateral auditory deprivation in early childhood can lead to cortical strengthening of inputs from the stimulated side, yet the impact of this on bilateral processing when inputs are later restored beyond an early sensitive period is unknown. To address this, we conducted a longitudinal study with 13 bilaterally profoundly deaf adolescents who received unilateral access to sound via a cochlear implant (CI) in their right ear in early childhood before receiving bilateral access to sound a decade later via a second CI in their left ear. Auditory‐evoked cortical responses to unilateral and bilateral stimulation were measured repeatedly using electroencephalogram from 1 week to 14 months after activation of their second CI. Early cortical responses from the newly implanted ear and bilateral stimulation were atypically lateralized to the left ipsilateral auditory cortex. Duration of unilateral deafness predicted an unexpectedly stronger representation of inputs from the newly implanted, compared to the first implanted ear, in left auditory cortex. Significant initial reductions in responses were observed, yet a left‐hemisphere bias and unequal weighting of inputs favoring the long‐term deaf ear did not converge to a balanced state observed in the binaurally developed system. Bilateral response enhancement was significantly reduced in left auditory cortex suggesting deficits in ipsilateral response inhibition of new, dominant, inputs during bilateral processing. These findings paradoxically demonstrate the adaptive capacity of the adolescent auditory system beyond an early sensitive period for bilateral input, as well as restrictions on its potential to fully reverse cortical imbalances driven by long‐term unilateral deafness.

Vocabulary Growth in Mandarin-Speaking Children With Bilateral Cochlear Implants, Bimodal Stimulation, or Unilateral Cochlear Implants During the First Year After Activation

PURPOSE

The purpose of this study was to evaluate vocabulary development in Mandarin-speaking children with bilateral cochlear implants (CIs), bimodal stimulation (CI plus hearing aids [HAs]), or unilateral CIs during the first year after CI activation.

METHOD

Participants included 23 children with simultaneous bilateral CIs, 23 children with bimodal stimulation, and 15 children with unilateral CIs. They all received CIs before 30 months of age. Parents were asked to endorse words that their child could understand only or understand and say using the Early Vocabulary Inventory for Mandarin Chinese at the day of CI activation and 1, 3, 6, 9, and 12 months after CI activation. Receptive and expressive vocabulary sizes were computed.

RESULTS

Growth curve analysis revealed that children with simultaneous bilateral CIs demonstrated faster growth of receptive vocabulary than those with bimodal stimulation, followed by those with unilateral CIs. Moreover, children with simultaneous bilateral CIs reached the 100-word mark for receptive vocabulary earlier than children with bimodal stimulation, followed by those with unilateral CIs. There were no significant differences among the three groups in expressive vocabulary.

CONCLUSIONS

Bilateral CIs have an advantage over bimodal stimulation in early receptive vocabulary development in Mandarin, a tone language. HA usage is still recommended for those who receive one CI.

Validity and Reliability of Turkish Version of the Auditory Behavior in Everyday Life Questionnaire

PURPOSE

This study aimed to investigate the validity and reliability of the Turkish version of the Auditory Behavior in Everyday Life (ABEL) questionnaire.

METHOD

The ABEL questionnaire was translated into Turkish using the "back-translation" method. The study included 130 parents of children with cochlear implantation, and 126 parents of children with typical hearing were included as a control group. In the study group, there were 62 unilateral and 68 bilateral cochlear implant (CI) users. The age at implantation ranged from 1 to 10 years, as they have substantial auditory skills. The participants' parents completed the ABEL individually, and 73 parents (28, study group; 45, control group) completed the ABEL again for test-retest reliability. Construct validity was tested using confirmatory factor analysis (CFA), and internal consistency was tested using Cronbach's alpha. Spearman's correlation test was used to assess the external validity of the total and all subscales of the ABEL and the Meaningful Auditory Integration Scale (MAIS). Test-retest reliability was measured using the intraclass correlation coefficient.

RESULTS

The Cronbach's α values for subscales ranged from .67 to .89, and the value was .93 (excellent) for the overall scale. External validity analyses showed moderate to strong correlations between the total and subscale scores of the ABEL and the MAIS, indicating high external validity. According to the CFA findings, the construct validity of the Turkish version of the ABEL was satisfactory. For the three-factor structure, the goodness-of-fit indices revealed a good fit, and only the normed fit index revealed an acceptable fit.

CONCLUSION

The Turkish version of the ABEL is a reliable and valid assessment tool for children with CIs.

Quality control in cochlear implant therapy: clinical practice guidelines and registries in European countries

PURPOSE

The treatment with a cochlear implant (CI) is the gold standard in therapy of patients with profound hearing loss or deafness. Successful hearing rehabilitation with a CI is a complex, multi-stage process. In medicine, "Clinical Practice Guidelines" (CPG) are widely accepted for the standardization of such processes. These are supplemented by medical registries in which data regarding the treatment can be collected and evaluated. The aim of this paper is to identify currently existing CI-related CPGs and registries in Europe.

METHODS

Between 01/2021 and 06/2021, 42 countries on the European continent, including the United Kingdom, Russia and Turkey, were screened using an internet search (search engine: Google) and a key word search in the Pubmed database. Search terms were the respective country name combined with the following terms: "Cochlear Implant", "CI", "Cochlear implant clinical practice guideline", "CI Guideline", "Cochlear Implant Registry", "CI Registry", "Ear nose throat society". The internet search was conducted in English as well as in the corresponding national language. The objective was to identify a CI-related CPG or registry.

RESULTS

A CPG was found in 16 of 42 (38%) countries. In terms of population, this accounts for 645 million out of 838 million people (77%). A registry existed in 4 of the 42 (10%) countries assessed. This corresponds to 102 million out of 838 million (12%) people. In total, 4 out of 42 countries (10%) had both a CPG and a registry.

CONCLUSION

Our work shows numerous efforts in Europe to standardize CI care at the national level. While most people in Europe already live in countries with a CPG, this is not the case for CI registries. European-wide consensus on CPGs or registries does not yet exist. The present study thus provides a first assessment of the distribution of CI-related CPGs and registries.

Early prelingual auditory and language development in children with simultaneous bilateral and unilateral cochlear implants

PURPOSE

This current study aimed to explore early prelingual auditory development (EPLAD) and early language development in Mandarin-speaking children who received simultaneous bilateral cochlear implants (BICI) during the first year of cochlear implantation and compare the performance of the children who received BICI with those received unilateral cochlear implant (UCI).

METHODS

39 Mandarin-speaking children who received BICIs simultaneously and 36 children with UCIs were enrolled in this study. To access the EPLAD, the Infant-Toddler Meaningful Auditory Integration Scale (IT/MAIS) was conducted, and a subtest of the simplified short-form version of the Mandarin Communicative Development Inventory (SSF-MCDI) was used to evaluate the development of expressive and receptive vocabulary for the children at indicated time points after surgery.

RESULTS

In both the simultaneous BICI and UCI groups, we observed significantly increased scores of the SSF-MCDI and IT/MAIS 1 year after the surgery. There are indications of early advantages in children with BICI in IT/MAIS scores (at 1, 3, and 6 months after activation). For early development of language, a great difference between the expressive vocabulary scores and the receptive vocabulary scores was observed in both groups. We found there were not significant differences between the two groups on expressive or receptive vocabulary scores, the use of more differentiated measures might be required in future research. We further found that the development of the receptive or expressive vocabulary is dramatically correlated with the age at implantation and the total scores of IT/MAIS for children with simultaneous BICIs.

CONCLUSION

These results may supplement the skills development of early language and auditory in Mandarin-native children with simultaneous CIs. It is obvious that children with normal hearing have mastery of receptive vocabulary before that of expressive vocabulary, which is the same as children with unilateral and bilateral CIs in this research. IT/MAIS total scores and age at CI were important factors for early language performance in children with simultaneous BICIs.

Exploring Factors Responsible for Delay in Pediatric Cochlear Implantation

OBJECTIVE

To identify and characterize demographic and socioeconomic factors associated with delays in cochlear implantation (CI) in children.

STUDY DESIGN

Retrospective.

SETTING

Tertiary pediatric CI referral center.

PATIENTS

All patients under 18 years of age receiving CI between March 2018 and February 2020.

INTERVENTIONS

CI.

MAIN OUTCOME MEASURES

Primary outcome measures included age at implantation and time from hearing loss diagnosis and candidacy evaluation to CI.

RESULTS

Seventy-two patients were identified (44% women, average age at implantation 4.9 yr). Age at implantation was older in patients with public, rather than private, insurance (6.0 ± 0.8 yr versus 3.1 ± 0.7 yr, p = 0.007) and those from low-income areas (8.6 ± 7.6 yr versus 2.4 ± 3.0 yr, p = 0.007). Time between hearing loss diagnosis and implantation was longer in publicly insured patients (4.1 ± 0.6 yr versus 2.2 ± 0.5 yr, p = 0.014). Time between identification as a CI candidate and implantation was longer in publicly insured patients (721 ± 107d versus 291 ± 64 d, p = 0.001). Among children with congenital profound hearing loss, publicly insured patients continued to be older at implantation (1.9 ± 0.2 versus 1.0 ± 0.2 yr, p = 0.008). Latinx children were more often publicly insured whereas white children were more often privately insured (p < 0.05). Publicly insured patients had delays in the pre-CI workup, including, in no particular order, vestibular evaluation (621 ± 132 d versus 197 ± 67 d, p = 0.007), developmental evaluation (517 ± 106 d versus 150 ± 56 d, p = 0.003), speech evaluation (482 ± 107 d versus 163 ± 65 d, p = 0.013), and children's implant profile (ChIP) assessment (572 ± 107d versus 184 ± 59d, p = 0,002). On ChIP evaluation, concerns regarding educational environment and support were higher in Spanish-speaking children (p = 0.024; p = 2.6 × 10-4) and children with public insurance (p = 0.016; p = 0.002).

CONCLUSIONS

Disparities in access to CI continue to affect timing of pediatric cochlear implantation.

Bimodal Fitting and Bilateral Cochlear Implants in Children With Significant Residual Hearing: The Impact of Asymmetry in Spatial Release of Masking on Localization

Purpose This study aimed to gain more insight into the primary auditory abilities of children with significant residual hearing in order to improve decision making when choosing between bimodal fitting or sequential bilateral cochlear implantation. Method Sound localization abilities, spatial release of masking, and fundamental frequency perception were tested. Nine children with bimodal fitting and seven children with sequential bilateral cochlear implants were included in the study. As a reference, 15 children with normal hearing and two children with simultaneous bilateral cochlear implants were included. Results On all outcome measures, the implanted children performed worse than the normal hearing children. For high-frequency localization, children with sequential bilateral cochlear implants performed significantly better than children with bimodal fitting. Compared to children with normal hearing, the left-right asymmetry in spatial release of masking was significant. When the implant was hindered by noise, bimodally fitted children obtained significantly lower spatial release of masking compared to when the hearing aid was hindered by noise. Overall, the larger the left-right asymmetry in spatial release of masking, the poorer the localization skills. No significant differences were found in fundamental frequency perception between the implant groups. Conclusions The data hint to an advantage of bilateral implantation over bimodal fitting. The extent of asymmetry in spatial release of masking is a promising tool for decision making when choosing whether to continue with the hearing aid or to provide a second cochlear implant in children with significant residual hearing.

A Scoping Review of Studies Comparing Outcomes for Children With Severe Hearing Loss Using Hearing Aids to Children With Cochlear Implants

OBJECTIVES

Clinical practice regarding children's candidature for cochlear implantation varies internationally, albeit with a recent global trend toward implanting children with more residual hearing than in the past. The provision of either hearing aids or cochlear implants can influence a wide range of children's outcomes. However, guidance on eligibility and suitability for implantation is often based on a small number of studies and a limited range of speech perception measures. No recent reviews have catalogued what is known about comparative outcomes for children with severe hearing-loss using hearing aids to children using cochlear implants. This article describes the findings of a scoping review that addressed the question "What research has been conducted comparing cochlear implant outcomes to outcomes in children using hearing aids with severe hearing-loss in the better-hearing ear?" The first objective was to catalogue the characteristics of studies pertinent to these children's candidature for cochlear implantation, to inform families, clinicians, researchers, and policy-makers. The second objective was to identify gaps in the evidence base, to inform future research projects and identify opportunities for evidence synthesis.

DESIGN

We included studies comparing separate groups of children using hearing aids to those using cochlear implants and also repeated measures studies comparing outcomes of children with severe hearing loss before and after cochlear implantation. We included any outcomes that might feasibly be influenced by the provision of hearing aids or cochlear implants. We searched the electronic databases Medline, PubMed, and CINAHL, for peer-reviewed journal articles with full-texts written in English, published from July 2007 to October 2019. The scoping methodology followed the approach recommended by the Joanna Briggs Institute regarding study selection, data extraction, and data presentation.

RESULTS

Twenty-one eligible studies were identified, conducted across 11 countries. The majority of children studied had either congenital or prelingual hearing loss, with typical cognitive function, experience of spoken language, and most implanted children used one implant. Speech and language development and speech perception were the most frequently assessed outcomes. However, some aspects of these outcomes were sparsely represented including voice, communication and pragmatic skills, and speech perception in complex background noise. Two studies compared literacy, two sound localization, one quality of life, and one psychosocial outcomes. None compared educational attainment, listening fatigue, balance, tinnitus, or music perception.

CONCLUSIONS

This scoping review provides a summary of the literature regarding comparative outcomes of children with severe hearing-loss using acoustic hearing aids and children using cochlear implants. Notable gaps in knowledge that could be addressed in future research includes children's quality of life, educational attainment, and complex listening and language outcomes, such as word and sentence understanding in background noise, spatial listening, communication and pragmatic skills. Clinician awareness of this sparse evidence base is important when making management decisions for children with more residual hearing than traditional implant candidates. This review also provides direction for researchers wishing to strengthen the evidence base upon which clinical decisions can be made.

Long-Term Language Development in Children With Early Simultaneous Bilateral Cochlear Implants

Objectives:

This longitudinal study followed the language development of children who received the combination of early (5 to 18 months) and simultaneous bilateral cochlear implants (CIs) throughout the first 6 years after implantation. It examined the trajectories of their language development and identified factors associated with language outcomes.

Design:

Participants were 21 Norwegian children who received bilateral CIs between the ages of 5 and 18 mo and 21 children with normal hearing (NH) who were matched to the children with CIs on age, sex, and maternal education. The language skills of these two groups were compared at 10 time points (3, 6, 9, 12, 18, 24, 36, 48, 60, and 72 months after implantation) using parent reports and standardized measures of general language skills, vocabulary, and grammar. In addition, assessments were made of the effects of age at CI activation, speech recognition abilities, and mothers’ education on language outcomes 6 years after implantation.

Results:

During the first 4 years after implantation, the gap in general expressive and receptive language abilities between children with CIs and children with NH gradually closed. While at the initial five to six assessments (3 to 36 months after implantation), significant differences between children with CIs and children with NH were observed; at 4 years after implantation, there were no longer any significant group differences in general language skills and most children with CIs achieved scores within 1 SD of the tests’ normative means. From 2 to 3 years after implantation onward, expressive vocabulary and receptive grammar skills of children with CIs were similar to those of the reference group. However, from 4 years after implantation until the end of the observation period, 6 years after implantation, expressive grammar skills of children with CIs were lower than those of children with NH. In addition, a gap in receptive vocabulary appeared and grew increasingly larger from 4 to 6 years postimplantation. At the final assessment, the children with CIs had an average receptive vocabulary score around 1 SD below the normative mean. Regression analysis indicated that the children’s language outcomes at 6 years after implantation were related to their speech recognition skills, age at CI activation, and maternal education.

Conclusions:

In the first 4 years after implantation, the language performance of children with CIs became increasingly similar to that of their NH peers. However, between 4 and 6 years after implantation, there were indications of challenges with certain aspects of language, specifically receptive vocabulary and expressive grammar. Because these challenges first appeared after the 4-year assessment, the findings underline the importance of long-term language intervention to increase the chances of a continued language development comparable to that of NH peers. They also indicate that there is a need for comprehensive longitudinal studies of the language development of children with CIs beyond 4 years after implantation.

Bimodal Stimulation in Children With Bilateral Profound Sensorineural Hearing Loss: A Suitable Intervention Model for Children at the Early Developmental Stage

OBJECTIVE

To evaluate the auditory and speech benefit of bimodal stimulation for prelingual deafened cochlear implantation recipients.

STUDY DESIGN

Retrospective and comparative study.

SETTING

Tertiary referral center.

PATIENTS

Fifty-six children with bilateral prelingual profound sensorineural hearing loss were enrolled, including 28 consecutive children with unilateral cochlear implantation (CI group), and 28 consecutive children with bimodal stimulation (BI group) who used an additional hearing aid (HA) in the contralateral ear.

MAIN OUTCOME MEASURES

Hearing assessments included the Infant-Toddler Meaningful Auditory Integration Scale (IT-MAIS) and Categories of Auditory Performance (CAP). Speech evaluations included the Meaningful Use of Speech Scale (MUSS), and Speech Intelligibility Rating (SIR). These measurements were evaluated at the first mapping of cochlear implants and 0.5, 1, 3, 6, 12, 18, 24 months after. Data were analyzed by repeated measures analysis.

RESULTS

The mean ages of BI and CI groups were similar (17.6 ± 6.87 vs 19.0 ± 8.10 months, p = 0.497). The initial scores for hearing and speech assessments showed no differences between the two groups, apart from IT-MAIS (2.46 ± 0.631 in BI group vs 0.50 ± 0.279 in CI group, p = 0.004). The auditory and speech development over time were different in the two groups as seen in IT-MAIS (p < 0.001), CAP (p = 0.029), MUSS (p < 0.001), and SIR (p < 0.001). A continuing but stable difference was observed in CAP, MUSS, and SIR at 3, 18, and 12 months after the first mapping, respectively. In addition, the BI group had better IT-MAIS scores at 3 and 6 months compared with the CI group; however, the difference was not significant after 12 months.

CONCLUSION

Bimodal stimulation is beneficial for prelingually deafened CI recipients who have minimal contralateral residual hearing when bilateral CIs are not available. Hearing aid use in the contralateral ear might be recommended for children after unilateral cochlear implantation to facilitate the development of auditory and speech skills.

Systematic Review of Quality of Life Assessments after Cochlear Implantation in Older Adults

Cochlear implants (CI) have increasingly been adopted in older adults with severe to profound sensorineural hearing loss as a result of the growing and aging world population. Consequently, researchers have recently shown great interest in the cost-effectiveness of cochlear implantation and its effect on quality of life (QoL) in older CI users. Therefore, a systematic review and critical evaluation of the available literature on QoL in older adult CI users was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Studies were selected by searching MEDLINE (PubMed) and the Cochrane Library and by checking the reference lists of relevant articles. Inclusion criteria were as follows: (1) the study sample were adults aged 50 years and older with postlingual onset of bilateral severe to profound hearing loss, (2) all subjects received a multi-electrode CI, and (3) QoL was assessed before and after implantation. Out of 1,093 records, 18 articles were accepted for review. Several studies demonstrated significant positive effects of cochlear implantation on QoL in older adults, but high-level evidence-based medicine is lacking. An improvement of QoL was generally reported when using disease-specific instruments, which are designed to detect treatment-specific changes, whereas the outcomes of generic QoL questionnaires, assessing general health states, were rather ambiguous. However, only generic questionnaires would be able to provide calculations of the cost-effectiveness of CI and comparisons across patient populations, diseases, or interventions. Hence, generic and disease-specific QoL instruments are complementary rather than contradictory. In general, older CI users' QoL was assessed using a variety of methods and instruments, which complicated comparisons between studies. There is a need for a standardized, multidimensional, and comprehensive QoL study protocol including all relevant generic and disease-specific instruments to measure and compare QoL, utility, and/or daily life performance in CI users.

Prelingual Deaf Children Treated With Cochlear Implant: Monitoring Performance With Percentiles

OBJECTIVES

To develop a percentile ranking system driven by speech recognition data obtained from different groups of patients treated with a cochlear implant to serve as a tool to monitor the progress of these patients.

STUDY DESIGN

Prospective study.

SETTING

Tertiary referral center.

PATIENTS

Diagnosed with a bilateral, profound sensorineural hearing loss treated with a unilateral cochlear implant.

INTERVENTION

Diagnostic.

MAIN OUTCOME MEASURE

Six different percentiles (p) were classified taking into account the correlation between speech recognition outcome scores and age at implantation, with reference to the onset of hearing loss.

RESULTS

Four hundred sixteen prelingual patients were included. These subjects were divided into subgroups depending on age at implantation.Prelingual group, from the fifth year after implantation, p50 centered on the following percentages of correct words in each subgroup: 100, 94.6, 91.4, 91.0, 79.2, and 63.1% in children implanted under 12 months, 1, 2, 3, 4 to 6, 7 to 10 years, respectively. After a 12-year follow-up, a significant negative correlation between age at implantation and speech recognition was observed in both prelinguals (Rhos=-0.578, p<0.001).

CONCLUSION

A percentile system was developed to monitor the postimplant progress of prelingual deaf implanted patients, with potential applications in patient follow-up and handling circumstances that may deteriorate results.

Cochlear Implantation With a Novel Long Straight Electrode: the Insertion Results Evaluated by Imaging and Histology in Human Temporal Bones

HYPOTHESIS

To evaluate the insertion results of a novel straight array (EVO) by detailed imaging and subsequent histology in human temporal bones (TB).

BACKGROUND

The main focuses of modern cochlear implant surgery are to prevent damage to the intracochlear structures and to preserve residual hearing. This is often achievable with new atraumatic electrode arrays in combination with meticulous surgical techniques.

METHODS

Twenty fresh-frozen TBs were implanted with the EVO. Pre- and postoperative cone beam computed tomography scans were reconstructed and fused for an artifact-free representation of the electrode. The array's vertical position was quantified in relation to the basilar membrane on basis of which trauma was classified (Grades 0-4). The basilar membrane location was modeled from previous histologic data. The TBs underwent subsequent histologic examination.

RESULTS

The EVOs were successfully inserted in all TBs. Atraumatic insertion (Grades 0-1) were accomplished in 14 of 20 TBs (70%). There were three apical translocations, and two basal translocations due to electrode bulging. One TB had multiple translocations. The sensitivity and specificity of imaging for detecting insertion trauma (Grades 2-4) was 87.5% and 97.3.0%, respectively.

CONCLUSION

Comparable insertion results as reported for other arrays were also found for the EVO. Insertion trauma can be mostly avoided with meticulous insertion techniques to prevent bulging and by limiting the insertion depth angle to 360 degrees. The image fusion technique is a reliable tool for evaluating electrode placement and is feasible for trauma grading.

BalanCI: Head-Referenced Cochlear Implant Stimulation Improves Balance in Children with Bilateral Cochleovestibular Loss

INTRODUCTION

To determine the impact of a head-referenced cochlear implant (CI) stimulation system, BalanCI, on balance and postural control in children with bilateral cochleovestibular loss (BCVL) who use bilateral CI.

METHODS

Prospective, blinded case-control study. Balance and postural control testing occurred in two settings: (1) quiet clinical setting and (2) immersive realistic virtual environment (Challenging Environment Assessment Laboratory [CEAL], Toronto Rehabilitation Institute). Postural control was assessed in 16 and balance in 10 children with BCVL who use bilateral CI, along with 10 typically developing children. Children with neuromotor, cognitive, or visual deficits that would prevent them from performing the tests were excluded. Children wore the BalanCI, which is a head-mounted device that couples with their CIs through the audio port and provides head-referenced spatial information delivered via the intracochlear electrode array. Postural control was measured by center of pressure (COP) and time to fall using the WiiTM (Nintendo, WA, USA) Balance Board for feet and the BalanCI for head, during the administration of the Modified Clinical Test of Sensory Interaction in Balance (CTSIB-M). The COP of the head and feet were assessed for change by deviation, measured as root mean square around the COP (COP-RMS), rate of deviation (COP-RMS/duration), and rate of path length change from center (COP-velocity). Balance was assessed by the Bruininks-Oseretsky Test of Motor Proficiency 2, balance subtest (BOT-2), specifically, BOT-2 score as well as time to fall/fault.

RESULTS

In the virtual environment, children demonstrated more stable balance when using BalanCI as measured by an improvement in BOT-2 scores. In a quiet clinical setting, the use of BalanCI led to improved postural control as demonstrated by significant reductions in COP-RMS and COP-velocity. With the use of BalanCI, the number of falls/faults was significantly reduced and time to fall increased.

CONCLUSIONS

BalanCI is a simple and effective means of improving postural control and balance in children with BCVL who use bilateral CI. BalanCI could potentially improve the safety of these children, reduce the effort they expend maintaining balance and allow them to take part in more complex balance tasks where sensory information may be limited and/or noisy.

What Is the Sensitive Period to Initiate Auditory Stimulation for the Second Ear in Sequential Cochlear Implantation?

OBJECTIVES

Bilateral cochlear implants (CI) are the standard treatment for bilaterally deaf children, but it is unclear how much the second CI can be delayed in sequential bilateral CI. We investigated the performances of sequential CI to answer this question.

STUDY DESIGN

Retrospective case series review.

SETTING

Tertiary referral center.

METHODS

We studied a cohort of congenitally deaf children (n = 73) who underwent sequential CI without any inner ear anomaly or combined disabilities. Hearing threshold levels and speech perception were evaluated by aided pure tone audiometry and Asan-Samsung Korean word recognition test. The scores were analyzed by the ages at surgery and compared among the different age groups.

RESULTS

When the second CI was performed before 3.5 years (the optimal period for the first CI), the second CI scores (96.9%) were comparable to the first CI scores. Although the first CI scores were more than or equal to 80% when the first CI was implanted before the age of 7 years, the second CI scores were more than or equal to 80% when the second CI was implanted before the age of 12 to 13 years. The hearing threshold levels were not different regardless of the ages and between the first and second CIs.

CONCLUSION

Our cohort demonstrated that the second CI showed comparable results to the first CI when implanted before 3.5 years, suggesting that optimal periods for the first CI and the second CI are same. However, the sensitive period (12-13 yr) for the second CI with good scores (≥80%) was much longer than that (7 yr) of the first CI, suggesting that the first CI prolongs the sensitive period for the second CI. The second CI should be implanted early, but considered even at a later age.

Cost-effectiveness analysis of bilateral cochlear implants for children with severe-to-profound sensorineural hearing loss in both ears in Singapore

A cochlear implant is a small electronic device that provides a sense of sound for the user, which can be used unilaterally or bilaterally. Although there is advocacy for the benefits of binaural hearing, the high cost of cochlear implant raises the question of whether its additional benefits over the use of an acoustic hearing aid in the contralateral ear outweigh its costs. This cost-effectiveness analysis aimed to separately assess the cost-effectiveness of simultaneous and sequential bilateral cochlear implantations compared to bimodal hearing (use of unilateral cochlear implant combined with an acoustic hearing aid in the contralateral ear) in children with severe-to-profound sensorineural hearing loss in both ears from the Singapore healthcare payer perspective. Incremental quality-adjusted life year (QALYs) gained and costs associated with bilateral cochlear implants over the lifetime horizon were estimated based on a four-state Markov model. The analysis results showed that, at the 2017 mean cost, compared to bimodal hearing, patients receiving bilateral cochlear implants experienced more QALYs but incurred higher costs, resulting in an incremental cost-effectiveness ratio (ICER) of USD$60,607 per QALY gained for simultaneous bilateral cochlear implantation, and USD$81,782 per QALY gained for sequential bilateral cochlear implantation. The cost-effectiveness of bilateral cochlear implants is most sensitive to utility gain associated with second cochlear implant, and cost of bilateral cochlear implants. ICERs increased when the utility gain from bilateral cochlear implants decreased; ICERs exceeded USD$120,000 per QALY gained when the utility gain was halved from 0.03 to 0.015 in both simultaneous and sequential bilateral cochlear implantations. The choice of incremental utility gain associated with the second cochlear implant is an area of considerable uncertainty.

Critical Factors for Binaural Hearing in Children with Bilateral Sequential Cochlear Implantation: First Implant Performance and Inter-Implant Interval

Objectives: This study evaluated the influence of the performance of the first cochlear implant (CI-1) on the second implant (CI-2) and the significance of inter-implant intervals in children with sequential cochlear implantation. Method: Thirty-four patients were included for speech perception outcome and 38 patients were included for subjective hearing satisfaction in daily life in this study. The patients were classified into 3 groups according to inter-implant interval: group I, <4 years; group II, 4–7 years; group III, >7 years. Open-set speech perception scores before and at 3, 6, 12, and 24 months after the second implantation was compared among the CI-1, CI-2, and bilateral CI conditions. Subjective hearing benefits in daily life were measured using a questionnaire of Speech, Spatial, and Qualities of Hearing Scale (SSQ) for parents of children with impaired hearing, and device use and preference were evaluated (by phone interview.) Results: The speech perception of children using the CI-2 only improved quickly within 3 months postoperatively and were similar to those using the CI-1 only. The results of monosyllabic and disyllabic word tests using CI-2 at 3 months after second implantation were not significantly different from those in patients using the CI-1 only. In the sentence test, the scores using the CI-2 only were not significantly different from those using the first implant only at 6 months after second implantation. SSQ scores were similar among groups and the worst score in each section was shown from the questions about performance under noisy conditions in each section. Device usage habits showed that 17 (44.7%) and 16 (42.1%) patients preferred bilateral and the CI-1, respectively. Only 5 (13.2%) patients wanted the CI-2 rather than the CI-1. While group I and II showed a prominent positive attitude to bilateral use, group III, for which the inter-implant interval was 7 years or more, showed a definite preference for the CI-1 (p < 0.01). Conclusions: Functional binaural benefits were achieved in patients who were good performers with the CI-1 after the second implantation irrespective of the inter-implant interval. Sequential CI should be strongly recommended for patients with unilateral CI showing a good performance.

Speech Perception Growth Patterns in Prelingual Deaf Children With Bilateral Sequential Cochlear Implantation

OBJECTIVE

To evaluate speech perception following the first (CI-1) and second (CI-2) cochlear implantation (CI) in children with sequential bilateral CI.

STUDY DESIGN

Retrospective.

PATIENTS

Seventy children with follow-up for 60 months post CI-1 and 36 months post CI-2.

MAIN OUTCOME MEASURES

Word recognition score (WRS) was the main outcome. WRSs were compared by age at CI operation (group A ≤ 3.5 yr, B 3.6-8.6, for CI-1; group I ≤ 3.5 yr, II 3.6-7.0, III 7.1-13, IV > 13, for CI-2).

RESULTS

For CI-1, the WRS of group A exceeded 80% at 24 months post procedure, earlier than group B (54 mo). Group A also had a shorter period of CI-1 use up to the WRS plateau than group B. CI-2 showed an initial burst of WRS growth much earlier than CI-1. This initial burst was most robust within 3 months in group II, but modest in group IV. The periods of CI-2 use (11-17 mo) up to the WRS plateau were much shorter than CI-1 (40-64 mo). Group I did not show the best WRS at 1 month post CI but later exceeded the other groups.

CONCLUSION

Children received an immediate benefit by a burst of WRS growth from CI-2 earlier than CI-1, even within 3 months, suggesting that CI-1 gets the auditory cortex ready to foster speech processing from CI-2. The CI-2 performance depends on age at CI-2 implantation and on CI-1 performance. Our current findings will be relevant for clinicians who are counselling parents on CI-2 surgery.

Language outcome in children with congenital hearing impairment: The influence of etiology

OBJECTIVES

To investigate the possible association between the etiology of hearing impairment (HI) and language outcome in children with congenital HI after an early medical-technical intervention and three years of AVT.

METHODS

A retrospective, two-center study was conducted of 53 patients who were divided in four categories of etiology (degeneratio labyrinthi acustici (DLA) congenita hereditaria, DLA congenita non specificata, DLA congenita postinfectiosa and auditory neuropathy). Language outcome was assessed by examining receptive vocabulary (Peabody Picture Vocabulary Test, PPVT-4), receptive language (Reynell test) and productive language (the Danish 'Viborgmaterialet'). All tests were conducted 1, 2 and 3 years after the children received their hearing device. Test scores were calculated from the child's chronological age. Analysis of possible associations was performed using Fisher's exact test and McNemar's test was conducted to examine possible differences between each year of testing for every speech-language test. Subsequently, univariate analyses were performed to search for other possible covariates associated with language outcome.

RESULTS

No significant associations were found between the etiology of the HI and the language outcome of children with HI after 1 year of AVT (PPVT, p = 0,234; Reynell, p = 0,845; Viborgmaterialet, p = 0,667), neither after 2 years of AVT (PPVT, p = 0,228; Reynell, p = 0,172; Viborgmaterialet, p = 0,659) nor after 3 years of AVT (PPVT, p = 0,102; Reynell, p = 0,512 Viborgmaterialet, p = 0,580). Some significant associations were found between language outcome and the type of hearing device and between language outcome and additional disabilities, however no strong evidence was found.

CONCLUSION

Most children with congenital HI developed a comparable level of speech and language regardless of the etiology of their HI. This study highlights the interest of further research using objective assessments techniques in a larger and more homogeneous population. If the findings from this study will be confirmed in future studies, this will have a clinical and societal impact regarding the diagnostics of HI.

Bilateral cochlear implantation is regarded as very beneficial: results from a worldwide survey by online questionnaire

PURPOSE

Bilateral cochlear implant (CI) provision is now widely regarded as the most beneficial hearing intervention for acceptable candidates. This study sought to determine if a number of well-regarded hearing professionals at highly reputable clinics shared similar practices and beliefs regarding bilateral CI provision, use, and rehabilitation in children and adults.

METHODS

An 11-question online questionnaire was created and distributed to all 27 clinics in the HEARRING group. Questions 1-5 asked for facts; questions 6-11 asked for opinions.

RESULTS

20 completed questionnaires were returned. All 20 respondents reported that their clinics perform bilateral cochlear implantation in children; 18 do so in adults. Regarding the fact-based questions, bilateral CI provision is more commonly performed and more likely to be reimbursed in children than in adults. Children are also much more likely to be implanted simultaneously than are adults. Regarding the opinion-based questions, respondents gave broadly similar answers. Communication between the CIs and speech coding strategies specifically developed for bilateral CI users were regarded as the two future technologies that would most enhance the benefit of bilateral CI use.

CONCLUSIONS

Most clinics in the HEARRING group are very familiar with bilateral CI provision and hold similar opinions on its results and benefits. Hopefully the results described herein will lead to a greater acceptance and regular reimbursement of bilateral CI provision, especially in adults.

An Analysis of Safety and Adverse Events Following Cochlear Implantation in Children Under 12 Months of Age

OBJECTIVE

To determine perioperative morbidity of children ≤12 months undergoing cochlear implantation (CI).

STUDY DESIGN

Retrospective analysis using the American College of Surgeons National Surgical Quality Improvement Program Pediatric Database (ACS-NSQIP-P).

SETTING

General acute care children's hospitals, children's hospitals within larger hospitals, specialty children's hospitals, and general acute care hospitals with a pediatric wing.

PATIENTS

Children who underwent CI were queried using the ACS-NSQIP-P from 2012 to 2015.

INTERVENTION

Cochlear implantation.

MAIN OUTCOME MEASURES

Risk factors analyzed include age, prematurity, and presence of congenital disorders. Outcomes analyzed include operative time, length of stay, general surgical complications, readmissions, and related reoperations.

RESULTS

Over the database accrual period, the percentage of children ≤12 months at the time of surgery increased from 2012 to 2015 (6.08-7.78%, p = 0.0752). Total operative time, length of stay (≥1 d), and readmissions for those ≤12 months were significantly greater compared with those >12 months at the time of surgery (p < 0.001, p = 0.0037, and p < 0.0001, respectively). There were no statistically significant differences in general surgical complications (i.e., superficial incisional surgical site infections, organ/space surgical site infections, and/or unplanned reoperations) in cases ≤12 months. Complications specific to CI such as facial nerve paralysis, cerebrospinal fluid leak, and mastoiditis were not recorded in the ACS-NSQIP-P.

CONCLUSION

Infants had no more general surgical complications in the immediate postoperative period compared with older children, although total operative time, length of stay, and readmissions were found to be significantly greater in frequency.

Cochlear implant - state of the art

Cochlear implants are the treatment of choice for auditory rehabilitation of patients with sensory deafness. They restore the missing function of inner hair cells by transforming the acoustic signal into electrical stimuli for activation of auditory nerve fibers. Due to the very fast technology development, cochlear implants provide open-set speech understanding in the majority of patients including the use of the telephone. Children can achieve a near to normal speech and language development provided their deafness is detected early after onset and implantation is performed quickly thereafter. The diagnostic procedure as well as the surgical technique have been standardized and can be adapted to the individual anatomical and physiological needs both in children and adults. Special cases such as cochlear obliteration might require special measures and re-implantation, which can be done in most cases in a straight forward way. Technology upgrades count for better performance. Future developments will focus on better electrode-nerve interfaces by improving electrode technology. An increased number of electrical contacts as well as the biological treatment with regeneration of the dendrites growing onto the electrode will increase the number of electrical channels. This will give room for improved speech coding strategies in order to create the bionic ear, i.e. to restore the process of natural hearing by means of technology. The robot-assisted surgery will allow for high precision surgery and reliable hearing preservation. Biological therapies will support the bionic ear. Methods are bio-hybrid electrodes, which are coded by stem cells transplanted into the inner ear to enhance auto-production of neurotrophins. Local drug delivery will focus on suppression of trauma reaction and local regeneration. Gene therapy by nanoparticles will hopefully lead to the preservation of residual hearing in patients being affected by genetic hearing loss. Overall the cochlear implant is a very powerful tool to rehabilitate patients with sensory deafness. More than 1 million of candidates in Germany today could benefit from this high technology auditory implant. Only 50,000 are implanted so far. In the future, the procedure can be done under local anesthesia, will be minimally invasive and straight forward. Hearing preservation will be routine.

Sequential pediatric bilateral cochlear implantation: The effect of time interval between implants

OBJECTIVE

To examine speech intelligibility in children subjected to sequential bilateral cochlear implants (CI) surgery and to assess the influence of the inter-stage interval duration.

INTRODUCTION

Binaural hearing recovery can have additional benefits, especially in speech and language development in patients with congenital profound sensorineural hearing loss; so recently there has been an increase in the number of children receiving bilateral CI.

METHODS

Twenty-seven children who underwent sequential bilateral cochlear implant (SBCI) with a short (1-3 yrs), medium (4-6 yrs) and long (7-12 yrs) range interval between both implantations, respectively, were evaluated. All patients underwent periodic speech perception test in quiet and noise after second implant activation in three conditions: with the first or second implant alone and with both implants. Results were examined according to the inter-stage interval.

RESULTS

Speech intelligibility in noise was significantly better under bilateral conditions than either ear alone, in all three groups. Small improvements were seen in quiet, especially in the third group (6-12 yrs).

CONCLUSION

Benefits of second implant in the early-implanted children and after a short inter-implant delay are more evident. However our study support that, even after a long period of deafness and despite a prolonged inter-stage interval, sequential bilateral cochlear implantation should be considered.

LEVEL OF EVIDENCE

Level 4.

Economic Evaluation of Treatments for Pediatric Bilateral Severe to Profound Sensorineural Hearing Loss: An Australian Perspective

OBJECTIVES

In Australia, surgical treatment options for children with bilateral severe to profound sensorineural hearing loss exist in a continuum ranging from unilateral cochlear implantation (CI), sequential bilateral CI through to simultaneous bilateral CI, depending on the condition. When treatment options are mutually exclusive, the mean costs and benefits of each treatment group are summed together to obtain the total mean costs and benefits. This enables an incremental analysis of treatment options in the context of the treated populations.The objective was to evaluate the cost-utility of current Australian CI treatment practices in children using domestic costs and consequences when compared with bilateral hearing aids (HAs).

RESEARCH DESIGN

Economic evaluation including a Markov model based on secondary sources.

SETTING

The base case modeled a government health payer perspective over a child's lifetime. Primary and secondary school education costs were also assessed.

INTERVENTION

Bilateral HAs compared with CI, including unilateral, sequential bilateral, or simultaneous bilateral CI weighted according to treatment.

MAIN OUTCOME MEASURES

Incremental costs per quality adjusted life year.

RESULTS

Approximately 42% of children in Australia with unilateral CI did not transition to sequential bilateral nor undergo simultaneous bilateral implantation. This differs from previous economic evaluations that assumed 100% of children transitioned to sequential bilateral CI treatment or were treated with simultaneous bilateral CI.The incremental cost utility of unilateral cochlear implantation compared with HAs was AUD 21,947/QALY. The weighted average incremental cost utility of the combined cochlear implantation treatment groups was AUD 31,238/QALY when compared with HAs.

CONCLUSION

Previous economic evaluations of cochlear implantation assumed 100% of unilaterally treated patients would transition to sequential bilateral or be treated with simultaneous bilateral implantation. This approach does not take into account the total treated population, where a proportion of patients are treated with unilateral CI.CI was cost effective when compared with HAs, and included children treated with unilateral, sequential bilateral, and simultaneous bilateral CI.The model was sensitive to the number of assessment and habilitation visits. Alternative health service models with cost efficiencies are needed to reduce after care costs.

Simultaneous bilateral cochlear implants: Developmental advances do not yet achieve normal cortical processing

BACKGROUND

Simultaneous bilateral cochlear implantation promotes symmetric development of bilateral auditory pathways but binaural hearing remains abnormal. To evaluate whether bilateral cortical processing remains impaired in such children, cortical activity to unilateral and bilateral stimuli was assessed in a unique cohort of 16 children who received bilateral cochlear implants (CIs) simultaneously at 1.97 ± 0.86 years of age and had ~4 years of CI experience, providing the first opportunity to assess electrically driven cortical development in the absence of reorganized asymmetries from sequential implantation.

METHODS

Cortical activity to unilateral and bilateral stimuli was measured using multichannel electro-encephalography. Cortical processing in children with bilateral CIs was compared with click-elicited activity in 13 normal hearing children matched for time-in-sound. Source activity was localized using the Time Restricted, Artefact and Coherence source Suppression (TRACS) beamformer method.

RESULTS

Consistent with dominant crossed auditory pathways, normal P1 activity (~100 ms) was weaker to ipsilateral stimuli relative to contralateral and bilateral stimuli and both auditory cortices preferentially responded to the contralateral ear. Right hemisphere dominance was evident overall. Children with bilateral CIs maintained the expected right dominance but differences from normal included: (i) minimal changes between ipsilateral, contralateral and bilateral stimuli, (ii) weaker than normal contralateral stimulus preference, (iii) symmetric activity to bilateral stimuli, and (iv) increased occipital lobe recruitment during bilateral relative to unilateral stimulation. Between-group contrasts demonstrated lower than normal activity in the inferior parieto-occipital lobe (suggesting deficits in sensory integration) and greater than normal left frontal lobe activity (suggesting increased attention), even during passive listening.

CONCLUSIONS

Together, findings suggest that early simultaneous bilateral cochlear implantation promotes normal-like auditory symmetry but that abnormalities in cortical processing consequent to deafness and/or electrical stimulation through two independent speech processors persist.

Cortical Representation of Interaural Time Difference Is Impaired by Deafness in Development: Evidence from Children with Early Long-term Access to Sound through Bilateral Cochlear Implants Provided Simultaneously

Accurate use of interaural time differences (ITDs) for spatial hearing may require access to bilateral auditory input during sensitive periods in human development. Providing bilateral cochlear implants (CIs) simultaneously promotes symmetrical development of bilateral auditory pathways but does not support normal ITD sensitivity. Thus, although binaural interactions are established by bilateral CIs in the auditory brainstem, potential deficits in cortical processing of ITDs remain. Cortical ITD processing in children with simultaneous bilateral CIs and normal hearing with similar time-in-sound was explored in the present study. Cortical activity evoked by bilateral stimuli with varying ITDs (0, ±0.4, ±1 ms) was recorded using multichannel electroencephalography. Source analyses indicated dominant activity in the right auditory cortex in both groups but limited ITD processing in children with bilateral CIs. In normal-hearing children, adult-like processing patterns were found underlying the immature P1 (∼100 ms) response peak with reduced activity in the auditory cortex ipsilateral to the leading ITD. Further, the left cortex showed a stronger preference than the right cortex for stimuli leading from the contralateral hemifield. By contrast, children with CIs demonstrated reduced ITD-related changes in both auditory cortices. Decreased parieto-occipital activity, possibly involved in spatial processing, was also revealed in children with CIs. Thus, simultaneous bilateral implantation in young children maintains right cortical dominance during binaural processing but does not fully overcome effects of deafness using present CI devices. Protection of bilateral pathways through simultaneous implantation might be capitalized for ITD processing with signal processing advances, which more consistently represent binaural timing cues.SIGNIFICANCE STATEMENT Multichannel electroencephalography demonstrated impairment of binaural processing in children who are deaf despite early access to bilateral auditory input by first finding that foundations for binaural hearing are normally established during early stages of cortical development. Although 4- to 7-year-old children with normal hearing had immature cortical responses, adult patterns in cortical coding of binaural timing cues were measured. Second, children receiving two cochlear implants in the same surgery maintained normal-like input from both ears, but this did not support significant effects of binaural timing cues in either auditory cortex. Deficits in parieto-occiptal areas further suggested impairment in spatial processing. Results indicate that cochlear implants working independently in each ear do not fully overcome deafness-related binaural processing deficits, even after long-term experience.

Bimodal Stimulation in Prelingually Deaf Children: Lessons from a Cross-sectional Survey

OBJECTIVE

(1) To survey the use of bimodal stimulation by prelingually deaf children receiving unilateral cochlear implantation and (2) to investigate demographic and audiologic factors explaining the use of bimodal stimulation.

STUDY DESIGN

Cross-sectional survey.

SETTING

Tertiary care institution.

SUBJECTS AND METHODS

The study included 44 unilaterally implanted prelingually deaf children from a single institution, with a minimum follow-up of 1 year. During routine follow-up visits, an examiner interviewed parents on their children's use of bimodal stimulation. At the same time, residual hearing and hearing aid gain in the contralateral ear were assessed.

RESULTS

Approximately half of patients (52%) used bimodal stimulation. On average, bimodal users showed better mean unaided and aided thresholds than nonbimodal users (P < .001). A mean 250- to 500-Hz unaided threshold ≤90 dB HL in the contralateral, nonimplanted ear was associated with a higher probability of bimodal use (P = .008). Parental satisfaction with the contralateral hearing aid was inversely correlated with mean 125- to 500-Hz and 1000- to 4000-Hz unaided thresholds (P < .001) and mean 250- to 500-Hz and 1000- to 4000-Hz aided thresholds (P < .001).

CONCLUSIONS

A mean 250- to 500-Hz unaided threshold ≤90 dB HL is associated with a higher probability of bimodal use by prelingually deaf children. Better residual hearing is associated with a higher degree of parental satisfaction with the contralateral hearing aid. This information could be useful to counsel parents of prelingually deaf children, when deciding between bimodal stimulation and simultaneous bilateral cochlear implantation.

The history of Cochlear™ Nucleus® sound processor upgrades: 30 years and counting

To review developments in sound processors over the past 30 years that have resulted in significant improvements in outcomes for Nucleus^® recipients.